a) Field of the Invention
The present invention relates to an automatic vehicular velocity control apparatus for an automotive vehicle to follow up a preceding vehicle which is running ahead of the vehicle at an appropriate inter-vehicle distance when the preceding vehicle has been recognized.
b) Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 11-59222 published on Mar. 12, 1999 exemplifies a previously proposed automatic vehicular velocity control apparatus to follow up a preceding vehicle which is running ahead of the vehicle at the same traffic lane at an appropriate inter-vehicle distance.
In the above-described control apparatus, a preceding vehicle follow-up run control system is constituted by an inter-vehicle distance control system and a vehicular velocity control system. A first gain fd by which an inter-vehicle distance deviation .DELTA.L is multiplied and a second gain fv by which a relative velocity .DELTA.V of the vehicle to the preceding vehicle is multiplied are set on the basis of a specific angular frequency .omega.M and a damping factor .zeta.M in a transfer function of the preceding vehicle follow-up run control system, a target relative velocity V* is calculated as follows: .DELTA.V*=(fd.times..DELTA.L+fv.times..DELTA.V), and a target vehicular velocity V* is calculated by subtracting the target relative velocity .DELTA.V* from the vehicular velocity V.sub.T of the preceding vehicle.
Then, if both of the first gain fd and the second gain fv are modified according to the detected value of the inter-vehicle distance, the response characteristic of the inter-vehicle distance control system is modified.